Mobility is essential to functioning independently, particularly in today's highly mobile society. Thus, mobility is of constant concern to those individuals who are incapable of walking or who are limited in their ability to walk normally.
Crutches and canes require the user to balance himself on the bottom tip of the support which contacts the walking surface. However, the rubber-coated tip of the crutch has a cross-sectional area of at most about 3 square inches which can slip on rocks, loose gravel, ice and wet or uneven surfaces. This is also true for canes, walkers and walking sticks.
Conventional crutches are uncomfortable and can be hazardous to the user. Crutches do not ergonomically fit people in a satisfactory manner. To prevent interference with the arms and body, conventional crutches must be used at an angle of 10.degree. off the vertical with the base tip away from the user's feet. Thus, conventional crutches cannot be correctly used in the vertical plane parallel to the user's body and they must be used so that the longitudinal axis thereof is not at a right angle to the walking surface. The angle at which the tip of the crutch contacts the ground not only from forward to rear, but also laterally, does not lend itself to proper traction. This lateral angle causes the fixed upper end of the crutch to place force against the upper ribs under the arms and the nerves in the axilla and in particular the radial nerve which can cause discomfort and injury. The forward and rear motion of the crutch and the resulting underarm motion causes abrasion by the upper end movement of a pressure point from a forward point to a rearward point under the arm as the crutches pivot relative to the ground from their forward to their rearward position. Thus, the practice is to place padding on the upper end of the crutch to prevent injury to the user.
Proper use of crutches require that no weight be placed on the underarm. The hands and arms are supposed to carry all the weight. Experience has shown that most users do not have sufficient arm and hand strength to accomplish this and often improperly use the crutches resulting in accidents and injuries.
Crutch mobility under normal use is dependent upon one leg of the user leaving the ground and swinging forward like a pendulum to the forward point where it contacts the walking surface. The foot in contact with the walking surface then acts as a fulcrum while the crutches move off the surface from the rear position to the forward position. Crutches therefore operate on the basis that the top of the crutch moves in the form of an arc with the apex in the vertical or upright position. This means that the user of a crutch must be raised then lowered by the use of the underarm rest. The effort required to move forward on a crutch is increased due to the need to have a force or momentum in the action sufficient to lift the user during each forward step of the crutch. This lifting force also places cyclic forces upward on the user's underarm and shoulders. When the user drops in the forward position, their feet or foot impacts the ground and can cause injury and discomfort especially to those with additional functional limitations or the elderly or frail.
It is therefore desirable to provide devices including a crutch for assisting the mobility of injured or handicapped individuals which provide a stable base structure that is ergonomically correct, does not require much instruction to use and minimizes the likelihood of slippage on wet or icy surfaces or that an uneven or rough walking surface will inhibit the stability of the crutch structure and thereby the mobility of the individual.
It is desirable to provide a crutch-like structure that minimizes the discomfort and possible injury to the individual's hand, feet, arm or underarm during use.